I only in the last year made the move from the stove with a 4 gallon pot to the garage with a 15 gallon pot and never noticed any off taste before since I always brewed with the lid off. I do partial mash....and usually do IPA's which i have never noticed any off tastes. But recently have made a couple of pale ale and they have all had an off flavor that i can't put my finger on. It almost has a "burnt" type flavor...

I do usually leave my lid cracked or the pot tends to want to boil over...but condensation does from and drips back in.....looks like my methods have changed!

I agree with all of the above. However it is unimportant if you are brewing with Extract. It really only applies to all-grain brewing since the DMS is gone out of extract.

don't the precursors begin to reform once you get the wort above the magic temp? or is that another myth?

Morticai, You are seriously beyond my experience level, but my understanding is that the precursor to DMS, which is SMM is entirely converted in a 90 minute boil. I'm sure that the process of getting DME or LME goes way beyond what it takes to convert all the SMM to DMS and then blow that off. However, I always take the safe route and defer to those more advanced than I.

I am pretty sure that anything I know about this is heresay from this forum.

I only in the last year made the move from the stove with a 4 gallon pot to the garage with a 15 gallon pot and never noticed any off taste before since I always brewed with the lid off. I do partial mash....and usually do IPA's which i have never noticed any off tastes. But recently have made a couple of pale ale and they have all had an off flavor that i can't put my finger on. It almost has a "burnt" type flavor...

I do usually leave my lid cracked or the pot tends to want to boil over...but condensation does from and drips back in.....looks like my methods have changed!

What is your batch size? I boil 40 liter batches (~49 liter preboil for a 90 minute boil) in a 50 liter pot and manage to avoid the worst of the boil overs with flame control. You really only need to see the wort turning over, it doesn't have to be leaping out of the pot.

Partially covered is fine. Think of how many breweries have enclosed kettles. But a study done many years ago concluded that you want at least 15% of your kettle surface uncovered.

Breweries have enclosed kettles, but they have stacks and probably exhaust fans too But still I'm sure partially covered is fine. The important point is letting steam escape before it condenses and returns to the wort.

Stacks with exhaust vents AND a condensate drip ring. Plus the kettle is domed. If you leave the flat lid on even partially, you'll notice that the underside is covered in steam condensation. That's the stuff that you don't want to fall back into your wort.

For monkeypimp- DMS tastes similar to creamed corn. Rolling Rock has that flavor defect. If you never picked it up in your beer, or Rolling Rock, you my have a very high sensitivity, or be flavor blind to it (some people are).

For monkeypimp- DMS tastes similar to creamed corn. Rolling Rock has that flavor defect. If you never picked it up in your beer, or Rolling Rock, you my have a very high sensitivity, or be flavor blind to it (some people are).

Now I know why I don't like Rolling Rock.

The story goes that they had a curve or kink in the exhaust chimney over the kettle and condensation would drop back in, causing the DMS precursor. When they opened a new brewery without this fault they lost so much customer base because "the beer wasn't the same" that they had to incorporate the defect into the new system.

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Jeff Gladish, Tampa (989.3, 175.1 Apparent Rennarian)Homebrewing since 1990AHA member since 1991, now a lifetime member BJCP judge since 1995

For monkeypimp- DMS tastes similar to creamed corn. Rolling Rock has that flavor defect. If you never picked it up in your beer, or Rolling Rock, you my have a very high sensitivity, or be flavor blind to it (some people are).

Now I know why I don't like Rolling Rock.

The story goes that they had a curve or kink in the exhaust chimney over the kettle and condensation would drop back in, causing the DMS precursor. When they opened a new brewery without this fault they lost so much customer base because "the beer wasn't the same" that they had to incorporate the defect into the new system.

Not to mention that AB bought them out and is brewing it in their breweries. I've heard that they sometimes have trouble making it taste that way in a well built brewery.